Collapsible tap



y 1933- s. F. NEWMAN 1,912,298

COLLAPS IBLE TAP Filed Dec. 16, 1930 2 Sheets-Sheet l gwvento'c SamuelFNEH/177312 May 30, 1933.

S. F. NEWMAN COLLABSIBLE TAP Fi1ed De0. l6 1930 2 Sheets-Sheet 2 4% f/if 5637 W "I 4L [EL-DEE": 1 l6 I I WW I w. E l r Y 50 "Z6 3/ /Z f7 m, Z6

aware! Samuel]? Newman.

Patented May 30, 1933 UNITED STATES PATENT OFFICE SAMUEL F. NEWMAN, 0FWAYNESBORO, PENNSYLVANIA, ASSIGNOR 'IO LANDIS MACHINE COMPANY, OFWAYNESBORO, PENNSYLVANIA, A CORPORATION OF PENN- SYLVANIA COLLAPSIBLETAP Application filed December 16, 1930. Serial No. 502,798.

This invention relates to collapsing taps and that when the head iswithdrawn the such as are used for cutting screw-threads in bored holes,such bored holes being of such a size and nature as will permitcollapsing of the thread producing cutters so that the tap can bewithdrawn from the bore without the necessity of backing it out.

An object of the invention is to provlde an improved collapsible tap.

A further object is to provide improved locking means for the tap and.improved means for collapsing the tap when the thread has been cut tothe desired length.

Further objects and advantages will become apparent as the descriptionproceeds.

Referring to the accompanying drawings, which are made a part hereof andon which similar reference characters indicate similar parts,

Figure 1 is a side elevation of the tap,

Figure 2, a face view with certain parts broken away in order to showmeans by which the threading elements are held,

Figure 3, a sectional'view showing means for closing the tap,

Figure 4, a longitudinal section showlng the cutters in thread cuttingposition,

Figure 5, a longitudinal section showing the cutters in collapsedposition, and

Figures 6 and 7 are detail views showing serrated. ends of an adjustingand securing screw for locking the head of the plunger in adjustedposition to vary the size of the work.

In the drawings reference character 10 indicates a stock or body memberhaving radial slots 11 at one end for receiving thread cutting elementsor chasers 12. The chasers are seated in the head 13 of a plunger 18,the plunger having axial movement in the stock to position the chasersradially of the head. A groove 14 of the chaser is engaged by a tongue15 on the plunger head 13. The bottom or inner edge of each chaser restson an outer seat 16 on the plunger head as is best shown in Figures 4and 5. It will be readily seen that the radial position of the chasersis deter mined by the axial position of the plunger head 13 andthatrwhen the head is in the forward position the chasers will bepositioned in their outermost or thread cutting position chasers aredrawn inward radially to move them out of engagement with the work or tothe collapsed position whereby the tap may be freely withdrawn from thework.

The head 13 is secured to the plunger 18 by a threaded pin 17, the innerend of which pin is positioned in a socket in the end of the plunger 18.The pin 17 has an enlarged end which prevents its being displaced fromthe socket in which it is held. The inner end of the pin 17 is serratedas shown in Figure 6 and is engaged by the serrated cooperating end of aplunger 19. The plunger 19 is urged outwardly by means of a spring 20.The plunger 19 is locked against rotary motion by means of a pin 21engaging a slot 9 said pin permitting the necessary axial movement ofthe plunger to permit rotation of the pin 17 to adjust the head 13axially for adjustment of the chasers. The serrations on the pin 17 andplunger 19 are such as that a rotation of the pin 17 through adistanceof one serration will result in a known radial movement.

position by means of a transversely slidablelatch 22. The latch passesthrough a slot in the plunger and has a cut-out portion 23 to permitretraction of the plunger. Preferably a hardened plate 24 is secured toone side of the plunger against which an inner edge of the latch 22engages. Mounted on the body member 10 is a latch controlling rin orcollar 25 having ears or lugs 26 in which are secured bolts 27 which aresecured at their forward ends to a ring 28 which engages the work. Thebolts 27 may be adjusted axially in the ears or lugs and locked inadjusted position by bolts 29. Seated in sockets in the collar 25 aretubes 30 in which tubes and sockets are positioned compression springs31. The closed ends of the tubes 30 are in contact with a collar or ring32. The ring 32 is secured to the plunger 18 by means of a pin 33 whichpasses through a slot in the body member 10, the slot permitting axialmovement of the ring or collar. A shank portion 34 extends rearwardly ofthe body member 10 which shank is adapted to be held in a machinesuitably adapted for doing the work required of a tap. The collar 25 hasa cored flange 35 in which is mounted a cam member 36, the cam memberbeing secured in position by means of bolts or screws 37. The cam memberis provided with beveled surfaces 38 to cooperate with correspondingsurfaces 39 on the latch 22. A lever 43 is pivoted in the stock and hasits inner end engageable with a side 40 of a slot in the plunger formoving the plunger forwardto reset.

the tap.

In operation with the cutters inthe position shown in Figure 4 relativerotary motion between the tap and the work will cause screw threads tobe cut in the work until the ringQS engages with the work. has occurredfurther axial movementof the tap will move the cam 36 to cause thebeveled edges 38'to move back and to force the latch 22 radiallyinwardly until the recess 23 regis-' ters with the edges of the plungerso that the plunger 18 may travel to the rear under pressure of springs31. This will occur as soon as the latch has slid off the hardened plate24 under the influence of the springs 31 engaging the ring 32. Theplunger 18 is withdrawn carrying with it the head 13 and moving thecutters radially inwardly. This collapses them or brings them to theposition shown in Figure 5 at which time the tap may be withdrawn fromthe work. hen

' the tap has been withdrawn the'operator then shoves rearwardly on thelever 43 the inner end of which engages in a slot 40 to move the plunger18 forwardly. 'When the plunger has been moved sufiiciently forward theslot through this plunger will be moved to the position at which thelatch'22 may freely slide laterally through it, at this time the bevelededges 38 again acting on the'eorresponding beveled edges 39 on the latchn move the latch radially outwardly until it latches orloeks the plungerin the forward osition. The 1 cutters are then positioned or makinganother cut and the operation proceeds as before. I In order to adjustthe size of the threaded work the operator may insert a suitable wrenchin a SOCkQtll in pin 17 and by rotat- "described in the specification,but only as indicated in the appended claims.

Having thus fully described my said invention, what I claim as new anddesire to se- 7 cure by Letters Patent, is:

\Vhen this plunger 18. -This adjusts 1. In a collapsible tap havingthread cutting elements and means for collapsing the cutting elementswhen threads of predetermined length have been out, means for adjustingthe thread cutting elements to vary the diameter of the work cutcomprising an adjustable screw having a serrated end said end engagingthe serrated end of a spring pressed friction locking plunger,substantially as set forth.

2. A collapsible tap comprising a body member having radial slots in itsforward end, thread cutting elements mounted in said slots, a plungeraxially slidable in the body member, said plunger-having cam grooves inits forward end engageable with corresponding ribs onthe inner edgesofthe thread cutting elements and biased rearwardly to retract thethread cutting elements, a ring positioned about the body member havingsecured thereon work engaging means for moving it axially of the bodymember, a slide movable through the body member and the said plunger,said slide having a cut out portion adapted. to receive a portion of theplunger, one edge of the cut-out portion engaging a correspondingabutting portion on the plunger to hold the plunger in fixed forwardposition during threading, the cut-out portion permitting retraction ofthe plunger when the slide has been moved radially to a predeterminedposition, a collar surrounding the body member and secured to the saidplunger, and resilient means carried by the said ring for moving thesaid collar to retract the'said plunger, and means on the said ringhaving cam surfaces engageable with corresponding cam surfaces on thesaid slide for moving the slide radially inwardly and outwardly of thebody member upon axial movement of the said ring in either direction,substantially asset forth. 7

3. In a collapsible tap having a body member and an axially slidableplunger therein for. collapsing thread cutting elements, a transverseslide in said body member means on said slide engaging with the plungerfor looking it in fixed forward position tohold the thread cutters'infixed position and movable to permit the plunger to collapse the threadcutters, a plurality of cams engageable with said slide for moving theslide in one direction by positive cam action .topermit collapsing ofthe thread cutters and in another direction to lock them in threadcutting position, substantially as set forth.

at. In a collapsible tap,a body member having radial slots thereinadapted to receive threading cutters, a plunger axially slidable in thebody member and'operably connected to said cutters to hold them inthread cutting position when the plunger is in a forward position andtocollapse the cutters when the plunger is in'a retracted position, alatch slidable. throughthe plunger and having an abutment in engagementwith a corresponding abutting portion on the plunger for locking thecutters in a fixed forward position during threading, said latch havinga cut out portion to receive the abutting portion of the plunger topermit the plunger to be retracted to collapse the cutters when theabutting portions are released, substantially as set forth.

5. In a collapsible tap, a body member having radial slots thereinadapted to receive threading cutters, a plunger axially slidable in thebody member and operably connected to said cutters to hold them inthread cutting position when the plunger is in a forward position and tocollapse the cutters when the plunger is in a retracted position, alatch slidable through the plunger and having an abutment in engagementwith a corresponding abutting portion on the plunger for locking thecutters in a fixed forward position during threading, said latch havinga cut out portion to receive the abutting portion of the plunger topermit the plunger to be retracted to collapse the cutters, and a camoperably connected to means engageable by the work for moving said slideby positive cam action in one direction to permit collapsing of thecutters and in the other direction to lock the plunger in fixed forwardposition to hold the cutters in threading position, substantially as setforth.

6. A collapsible tap comprising a body portion having radial slots inits forward end, an axially adjustable plunger positioned in said bodymember, said plunger having beveled slots therein, radially positionedcutters mounted in said slots and extending through the slots in the endof the body member, a slide positioned in the body member and extendingthrough said plunger, a portion of the slide engaging a portion of theplunger to hold the plunger in fixed forward position to hold the threadcutters in fixed radial position during threading, said slide havingcams cut in its outer end, a ring positioned about said body portion andmovable by the work, said ring carrying a cam engaging with the cam onthe said slide to move the slide radially inwardly to permit retractionof the cutters, the cutters being held in fixed cutting position untilthe thread of a predetermined length has been cut, and means for quicklywithdrawing the plunger when released by the said slide to efiectsubstantially instantaneous retraction of the plunger and cutters,substantially as set forth.

In witness whereof, I have hereunto set my hand at lVaynesboro,Pennsylvania, this 12th day of December, A. D. nineteen hundred andthirty.

SAMUEL F. NEWMAN.

